OK, so my wife has what I think is called a three speed utility bike. In England we'd probably call it "Junk" It's a Sturmey Archer three speed hub probably 20+ years old. Having been doing bike mechanics for over a week now, hooray, I'm considering upgrading the bike to having straight handle bars and derailleur gears. More fool me perhaps! Having looked at the back end there seems to be nothing to hand a derailleur off. I just see a dropout for a hub wheel and bits for a bike rack. Do I have any option in upgrading?